The quest for a practical short take-off and landing aircraft (STOL) has led to a number of prior art proposals in recent times. Some examples of the patented prior art are shown in U.S. Pat. Nos. 2,973,922; 3,276,727; 3,432,123 and 3,525,486.
The objective of this invention is to improve on the known prior art in terms of a lift augmentation means for an aircraft wing, which is simpler in construction and more reliable and efficient than prior art devices.
More particularly, by means of the invention, high velocity heated air from the aircraft jet engines is diverted by known means into aircraft wing ducts, parallel to and near the leading edge of the wing. Each duct is of spiral formation in cross section with an outlet slit opening through the top of the wing near and rearwardly of its leading edge and directing a high velocity air stream rearwardly over the high lift wing surface and toward the trailing edge of the wing. A wing slat covers the outlet slit when the latter is inactive and lies flush against the wing and conforms to the adjacent wing contour. The slat is elevated by the action of the high velocity air stream leaving the wing slit, and the slat directs the air stream rearwardly across the dorsal surface of the wing to materially augment the lift capability of the wing. With properly chosen dimensional parameters for the invention in relation to the wing of a jet aircraft, the aircraft will be able to take off at approximately 50 miles per hour and land at a considerably lower speed.
The trailing edge portion of the elevatable slat is fixedly attached to an underlying grid through which the high velocity rearwardly moving air stream flows, and this grid in cooperation with the slat imparts laminar flow to the lift augmentation air stream. When the slat is retracted, the grid descends into a recess provided in the top of the wing and the slat assumes a flush position on the wing in covering relationship to the wing slit. Within the wing, conventional hydraulic means is provided to retract the slat and attached grid.